One last thing... taxes. You need to predict your earnings before and after retirement age, and your tax burden, and look at what Roth IRA or 401k can do for you and which would serve you best. You may also want to shelter some assets in some sort of trust, too. The hypothetical buy and hold account can be one of these. There are limits on when and how you draw down on these accounts and also for borrowing against, but since it is meant to be a buy and hold thing anyway, no reason why it can't be in stocks or partly in stocks. It doesn't have to be all about mutual funds and stuff. When I say stocks, I mean ETF's, too. Reducing your taxable income can be a huge benefit. Deferred taxation on contributions can be a good thing, depending on where you forecast your tax status to be when you start drawing out of it. Paid expert advice NOW would be money well spent. Thanks to the magic of compounding, getting started in your retirement investments NOW makes a huge impact on your old age nest egg. It kinda sucks to be young and poor but it sucks greatly to be old and poor, and being old and rich isn't such a bad gig.
For the beginners, it is always efficient so go trading with small amounts. If you want to keep building on the $500 you are initially investing, micro-investing can be a good approach here. Also, if you are looking for a way for keeping the money liquid with low risks associated with trading and want to go for a long-term game, consider opening up a high-interest savings account.